Charged-particle beam apparatus with beam-tilt and methods thereof

Abstract

Systems and methods of imaging a sample using a tilted charged-particle beam. The apparatus may comprise a first deflector located between the charged-particle source and an objective lens and configured to deflect the charged-particle beam away from the primary optical axis; a second deflector located substantially at a focal plane of the objective lens and configured to deflect the charged-particle beam back towards the primary optical axis; and a third deflector located substantially at a principal plane of the objective lens, wherein the third deflector is configured to shift a wobbling center of the objective lens to an off-axis wobbling location, and wherein the first and the second deflectors are configured to deflect the charged-particle beam to pass through the off-axis wobbling location to land on a surface of a sample at a first landing location and having a beam-tilt angle.

1 . A charged-particle beam apparatus, comprising:
 a charged-particle source configured to generate a charged-particle beam along a primary optical axis; and   a first deflector configured to deflect the charged-particle beam to land on a surface of a sample at a beam-tilt angle, wherein the first deflector is located substantially at a principal plane of an objective lens.   
     
     
         2 . The apparatus of  claim 1 , wherein the objective lens is configured to focus the charged-particle beam on the surface of the sample at an off-axis location, the charged-particle beam having the beam-tilt angle. 
     
     
         3 . The apparatus of  claim 1 , wherein the first deflector is configured to deflect the charged-particle beam based on a first electrical excitation signal comprising a static component and a dynamic component. 
     
     
         4 . The apparatus of  claim 3 , wherein:
 the static component is configured to cause the charged-particle beam having the beam-tilt angle land on the surface at an off-axis location; and   the dynamic component is configured to cause the beam to scan a field-of-view (FOV) on the surface, wherein a center of the FOV substantially coincides with the off-axis location.   
     
     
         5 . The apparatus of  claim 4 , wherein an adjustment of the dynamic component causes an adjustment of a size of the FOV, and an adjustment of the static component is configured to enable an adjustment of the off-axis location and the beam-tilt angle. 
     
     
         6 . The apparatus of  claim 2 , further comprising a second deflector located substantially at a front focal plane of the objective lens. 
     
     
         7 . The apparatus of  claim 6 , wherein the second deflector is located between a condenser lens and the first deflector along the primary optical axis. 
     
     
         8 . The apparatus of  claim 6 , wherein the second deflector is configured to deflect the charged-particle beam to scan a field-of-view (FOV) based on a dynamic component of a second electrical excitation signal, and wherein a center of the FOV substantially coincides with the off-axis location. 
     
     
         9 . The apparatus of  claim 8 , wherein an adjustment of the dynamic component of the second electrical excitation signal is configured to cause an adjustment of a size of the FOV, and an adjustment of a first electrical excitation signal of the first deflector is configured to enable an adjustment of the center of the FOV. 
     
     
         10 . A method for imaging a sample using a tilted charged-particle beam, the method comprising:
 generating a charged-particle beam along a primary optical axis; and   deflecting, using a first deflector, the charged-particle beam to land on a surface of a sample at a beam-tilt angle and at an off-axis location, wherein the first deflector is located substantially at a principal plane of an objective lens.   
     
     
         11 . The method of  claim 10 , further comprising deflecting, using the first deflector, the charged-particle beam based on a first electrical excitation signal comprising a static component and a dynamic component. 
     
     
         12 . The method of  claim 11 , further comprising:
 applying the static component of the first electrical excitation signal to the first deflector to deflect the charged-particle beam to land on the surface at the off-axis location; and   applying the dynamic component of the first electrical excitation signal to the first deflector to deflect the charged-particle beam to scan a field-of-view (FOV) on the surface, wherein a center of the FOV substantially coincides with the off-axis location.   
     
     
         13 . The method of  claim 12 , further comprising adjusting the dynamic component to adjust a size of the FOV, and adjusting the static component to adjust the off-axis location and the beam-tilt angle. 
     
     
         14 . The method of  claim 10 , further comprising:
 applying a dynamic component of a second electrical excitation signal to a second deflector to deflect the charged-particle beam to scan a field-of-view (FOV) on the surface, wherein a center of the FOV substantially coincides with the off-axis location; and   adjusting a dynamic component of the second electrical excitation signal applied to the second deflector to adjust a size and an orientation of the FOV, and adjusting a static component of a first electrical excitation signal to adjust a center of the FOV, wherein the second deflector is located substantially at a front focal plane of the objective lens.   
     
     
         15 . A non-transitory computer readable medium storing a set of instructions that is executable by one or more processors of a charged-particle beam apparatus to cause the charged-particle beam apparatus to perform a method of imaging a sample using a tilted charged-particle beam, the method comprising:
 activating a charged-particle source to generate a primary charged-particle beam;   deflecting, at a first deflector, the charged-particle beam to land on a surface of a sample at a beam-tilt angle, wherein the first deflector is located substantially at a principal plane of an objective lens.   
     
     
         16 . A charged-particle beam apparatus, comprising:
 a charged-particle source configured to generate a charged-particle beam along a primary optical axis;   a first deflector configured to deflect the charged-particle beam away from the primary optical axis; and   a second deflector configured to deflect the charged-particle beam back towards the primary optical axis so as to pass through a wobbling center of an objective lens and land on a surface of a sample at a beam-tilt angle, wherein the second deflector is positioned between the first deflector and the sample.   
     
     
         17 . The apparatus of  claim 16 , wherein the objective lens is configured to focus the charged-particle beam on the surface at an off-axis location, the charged-particle beam having the beam-tilt angle. 
     
     
         18 . The apparatus of  claim 16 , wherein the first deflector is located between a condenser lens and the second deflector. 
     
     
         19 . The apparatus of  claim 16 , wherein:
 the first deflector is configured to deflect the charged-particle beam based on a first static component and a first dynamic component of a first electrical excitation signal;   the second deflector is configured to deflect the charged-particle beam based on a second static component and a second dynamic component of a second electrical excitation signal;   the first and the second static components are configured to deflect the charged-particle beam to form an off-axis location and the beam-tilt angle; and   the first and the second dynamic components are configured to deflect the charged-particle beam to pass through the wobbling center and scan a field-of-view (FOV) on the surface of the sample.   
     
     
         20 . The apparatus of  claim 19 , wherein adjustments of the first and the second dynamic components cause an adjustment of a size of the FOV, and wherein adjustments of the first and the second static components are configured to cause an adjustment of the off-axis location and the beam-tilt angle.